This is a resubmission of a methodological study to develop a mathematical index of the structural aspects and contextual factors of professional nursing practice evident on acute care inpatient units. The current proposal includes methodological improvements and the addition of Ralph O'Brien, a statistician, to the research team. Studies of the variations in physician behavior and patient severity have not sufficiently explained differential outcomes among hospitalized patients. It is plausible that factors of nursing care, embodied in the nursing practice model (NPM) provide alternative explanations in aggregate patient outcomes. Using multiattribute utility theory, an index will be created to characterize nursing practice models on acute care units. This index will provide a stable numerical estimate of the extent to which a nursing unit's effort meets selected practice standards. Such an index, once developed, may be used to detect regional or institutional variations in nursing practice. The index may also be useful to hospital and nursing administrators who seek to change the NPMs in their institutions in order to achieve efficiencies and improve patient outcomes. A preliminary model gleaned from reports of the initiatives,to strengthen hospital nursing and improve patient care in 30 hospitals, included the following components of NPMs: specification of patient and nurse characteristics, stated goals of care, scope of nursing practice, and resource allocations strategies. Seven nurse experts, identified through a snow-ball sampling strategy, will be empaneled to validate this preliminary model. To complete the index process, the panelists will also assign relative importance weights to each component. Scales will be constructed and validated to measure each of the model Components. Once constructed, the index will be tested on 30 inpatient nursing units. Each unit will be assessed twice: once by a team of nurse surveyors, and once using the index. This descriptive study will validate the index of nursing practice models as a measure of the group effort of nursing. This validated index will provide an efficient and feasible measure of the context of clinical care that can then be applied in later investigations of the factors that contribute to successful patient outcomes in acute care.